Spinlock Handler

This handler encapsulates functionality which provides the foundation Spinlock services used in all of the APIs supported by RTEMS. More...

Collaboration diagram for Spinlock Handler:

Files
file	corespinlock.c
	Initialize a Spinlock.
file	corespinlockrelease.c
	Release a Spinlock.

Data Structures
struct	CORE_spinlock_Attributes
	The following defines the control block used to manage the attributes of each spinlock. More...
struct	CORE_spinlock_Control
	The following defines the control block used to manage each spinlock. More...

Macros
#define	CORE_SPINLOCK_STATUS_LAST   CORE_SPINLOCK_UNAVAILABLE
	This is a shorthand for the last status code. More...
#define	CORE_SPINLOCK_UNLOCKED   0
	This indicates the lock is available. More...
#define	CORE_SPINLOCK_LOCKED   1
	This indicates the lock is unavailable. More...

Enumerations
enum	CORE_spinlock_Status {   CORE_SPINLOCK_SUCCESSFUL, CORE_SPINLOCK_HOLDER_RELOCKING, CORE_SPINLOCK_NOT_HOLDER, CORE_SPINLOCK_TIMEOUT,   CORE_SPINLOCK_IS_BUSY, CORE_SPINLOCK_UNAVAILABLE }
	Core Spinlock handler return statuses. More...

Functions
void	_CORE_spinlock_Initialize (CORE_spinlock_Control *the_spinlock, CORE_spinlock_Attributes *the_spinlock_attributes)
	Initialize the spinlock. More...
CORE_spinlock_Status	_CORE_spinlock_Wait (CORE_spinlock_Control *the_spinlock, bool wait, Watchdog_Interval timeout)
	Wait for spinlock. More...
CORE_spinlock_Status	_CORE_spinlock_Release (CORE_spinlock_Control *the_spinlock)
	Manually release the spinlock. More...
RTEMS_INLINE_ROUTINE void	_CORE_spinlock_Initialize_attributes (CORE_spinlock_Attributes *the_attributes)
	This method is used to initialize core spinlock attributes. More...
RTEMS_INLINE_ROUTINE bool	_CORE_spinlock_Is_busy (CORE_spinlock_Control *the_spinlock)
	This method is used to determine if the spinlock is available or not. More...

Detailed Description

This handler encapsulates functionality which provides the foundation Spinlock services used in all of the APIs supported by RTEMS.

Macro Definition Documentation

CORE_SPINLOCK_LOCKED

#define CORE_SPINLOCK_LOCKED   1

This indicates the lock is unavailable.

Referenced by _CORE_spinlock_Release().

CORE_SPINLOCK_STATUS_LAST

#define CORE_SPINLOCK_STATUS_LAST   CORE_SPINLOCK_UNAVAILABLE

This is a shorthand for the last status code.

Referenced by _POSIX_Spinlock_Translate_core_spinlock_return_code().

CORE_SPINLOCK_UNLOCKED

#define CORE_SPINLOCK_UNLOCKED   0

This indicates the lock is available.

Enumeration Type Documentation

CORE_spinlock_Status

enum CORE_spinlock_Status

Core Spinlock handler return statuses.

Enumerator
CORE_SPINLOCK_SUCCESSFUL	This status indicates that the operation completed successfully.
CORE_SPINLOCK_HOLDER_RELOCKING	This status indicates that the current thread already holds the spinlock. An attempt to relock it will result in deadlock.
CORE_SPINLOCK_NOT_HOLDER	This status indicates that the current thread is attempting to unlock a spinlock that is held by another thread.
CORE_SPINLOCK_TIMEOUT	This status indicates that a thread reached the limit of time it was willing to wait on the spin lock.
CORE_SPINLOCK_IS_BUSY	This status indicates that a thread is currently waiting for this spin lock.
CORE_SPINLOCK_UNAVAILABLE	This status indicates that the spinlock is currently locked and thus unavailable.

Function Documentation

_CORE_spinlock_Initialize()

void _CORE_spinlock_Initialize	(	CORE_spinlock_Control *	the_spinlock,
		CORE_spinlock_Attributes *	the_spinlock_attributes
	)

Initialize the spinlock.

This routine initializes the spinlock based on the parameters passed.

Parameters

[in]	the_spinlock	is the spinlock control block to initialize
[in]	the_spinlock_attributes	define the behavior of this instance

References CORE_spinlock_Control::Attributes, CORE_spinlock_Control::holder, CORE_spinlock_Control::lock, and CORE_spinlock_Control::users.

_CORE_spinlock_Initialize_attributes()

RTEMS_INLINE_ROUTINE void _CORE_spinlock_Initialize_attributes

(

CORE_spinlock_Attributes *

the_attributes

)

This method is used to initialize core spinlock attributes.

Parameters

[in]

the_attributes

pointer to the attributes to initialize.

References CORE_spinlock_Attributes::XXX.

_CORE_spinlock_Is_busy()

RTEMS_INLINE_ROUTINE bool _CORE_spinlock_Is_busy

(

CORE_spinlock_Control *

the_spinlock

)

This method is used to determine if the spinlock is available or not.

Parameters

[in]

the_spinlock

will be checked

Returns

This method will return true if the spinlock is busy and false otherwise.

References CORE_spinlock_Control::users.

_CORE_spinlock_Release()

CORE_spinlock_Status _CORE_spinlock_Release

(

CORE_spinlock_Control *

the_spinlock

)

Manually release the spinlock.

This routine manually releases the spinlock. All of the threads waiting for the spinlock will be readied.

Parameters

[in]

the_spinlock

is the spinlock to surrender

References _ISR_Disable, CORE_SPINLOCK_LOCKED, CORE_spinlock_Control::holder, and CORE_spinlock_Control::lock.

_CORE_spinlock_Wait()

CORE_spinlock_Status _CORE_spinlock_Wait	(	CORE_spinlock_Control *	the_spinlock,
		bool	wait,
		Watchdog_Interval	timeout
	)

Wait for spinlock.

This routine wait for the spinlock to be released. If the spinlock is set to automatic and this is the appropriate thread, then it returns immediately. Otherwise, the calling thread is blocked until the spinlock is released.

Parameters

[in]	the_spinlock	is the spinlock to wait for
[in]	wait	is true if willing to wait
[in]	timeout	is the maximum number of ticks to spin (0 is forever)

Return values

A	status is returned which indicates the success or failure of this operation.